Low Loss Magnetic Thin Films for Off-Line Power Conversion

Advances in wide bandgap semiconductors have facilitated an increase in switching frequencies of power supplies. Higher switching frequencies are key to reducing the size of power components. However, miniaturization of magnetic passive components at high frequencies is still a challenge. Soft magnetic high flux density thin films are being widely researched as a replacement for ferrite cores. The existing thin film solutions have an inferior power loss performance compared to the best-in-class ferrites (500-600 kW/m³ at 500 kHz and 100 mT peak field) for the same frequency. In this paper, we discuss details of a post-processing technique for nanocrystalline thin film to achieve a power loss density of 200 kW/m³ at 500 kHz with peak flux density of 100 mT.